Quadratus lumborum

A quadrilateral muscle situated in the lower back, vital for spinal stability and movement.

The quadratus lumborum is a muscle located in the posterior abdominal wall, forming an important part of the lower back. It is a rectangular muscle that originates from the iliac crest and the iliolumbar ligament and attaches to the lower ribs and the lumbar vertebrae. It plays a significant role in various movements and stabilizations of the spine.

Terminologia Anatomica

quadratus-lumborum

System

Musculoskeletal system

Function

This muscle is essential for numerous functions, particularly in maintaining posture and facilitating movement of the torso. It aids in lateral flexion of the spine, allowing the trunk to bend sideways. Additionally, when both sides of the quadratus lumborum contract, it assists in extending the lumbar spine and stabilizing the pelvis. Its pivotal role in stabilizing the lower back during activities, such as lifting and stretching, cannot be overstated, as it helps prevent injuries and maintains proper alignment and function throughout the body. Furthermore, the quadratus lumborum contributes to respiratory mechanics by stabilizing the diaphragm and assisting in forced exhalation by pulling down the lower ribs.

Location

The quadratus lumborum is located in the lower back, posterior to the abdominal cavity, and lateral to the vertebral column. It spans from the iliac crest of the pelvis and the iliolumbar ligament, extending upward to the lower margins of the last rib and the transverse processes of the lumbar vertebrae. This positioning places it deep within the lumbar region, effectively acting like a bridge between the pelvis and the spine, and integrating the lower back with other regions of the body through its connection to the pelvis and ribs.

Did You Know?

The quadratus lumborum is often referred to as the 'muscle of the lower back' due to its significant role in lumbar stability.
This muscle can become tense or tight due to poor posture, prolonged sitting, or repetitive motions, leading to lower back pain.
In some individuals, the quadratus lumborum may exhibit variations in size and attachment points, potentially influencing its function.